Process for Forming Thermoplastic Vulcanizates and Thermoplastic Vulcanizates Made Therefrom
AssigneeExxonMobil Chemical Patents Inc.
InventorsDeclan Whelan, Stephen F. Roche, Porter C. Shannon
Life of this patent
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Abstract
Provided are methods for producing a thermoplastic vulcanizate and thermoplastic vulcanizates provided therein. The method includes introducing vulcanizable rubber, thermoplastic resin, a masterbatch of a propylene-based elastomer and a cure accelerator for a phenolic resin curative to the reactor, and phenolic resin curative to a reactor and dynamically vulcanizing the rubber with the phenolic resin curative in the presence of the cure accelerator and the thermoplastic resin.
Claims15
A composition comprising propylene-based elastomer and from about 10 wt % to about 90 wt % stannous chloride, based on the weight of the composition,
- where the propylene-based elastomer comprises propylene-derived units and 5 to 30 wt % of α-olefin-derived units and where the propylene-based elastomer has a melting temperature of less than 120° C. and a heat of fusion of less than 75 J/g.
A process for making a thermoplastic vulcanizate, the process comprising the steps of:
- (a) introducing a vulcanizable rubber to a reactor;
- (b) introducing a thermoplastic resin to the reactor;
- (c) introducing a masterbatch comprising a propylene-based elastomer and a cure accelerator for a phenolic resin curative to the reactor, where the propylene-based elastomer comprises propylene-derived units and 5 to 30 wt % of α-olefin-derived units and where the propylene-based elastomer has a melting temperature of less than 120° C. and a heat of fusion of less than 75 J/g;
- (d) introducing a phenolic resin curative to the reactor;
- and
- (e) dynamically vulcanizing the rubber with the phenolic resin curative in the presence of the cure accelerator and the thermoplastic resin.
A method for making a thermoplastic vulcanizate, the method comprising the steps of:
- (a) mixing a vulcanizable rubber and a thermoplastic resin above the melt temperature of the thermoplastic resin to form a molten mass;
- (b) adding a masterbatch comprising a propylene-based elastomer and a cure accelerator to the molten mass, where the propylene-based elastomer comprises propylene-derived units and 5 to 30 wt % of α-olefin-derived units and where the propylene-based elastomer has a melting temperature of less than 120° C. and a heat of fusion of less than 75 J/g;
- (c) melting the propylene-based elastomer of the masterbatch to thereby disperse the cure accelerator within the molten mass;
- (d) adding a phenolic curative to the molten mass;
- and
- (e) dynamically vulcanizing the rubber with the phenolic resin in the presence of the cure accelerator.
A method for making a thermoplastic vulcanizate, the method comprising the steps of:
- adding a ethylene-propylene-diene copolymer to a twin-screw extruder through the feed throat of the extruder;
- adding polypropylene to the twin-screw extruder through the feed throat of the extruder;
- mixing, within an initial mix zone, the ethylene-propylene-diene copolymer and the polypropylene at a temperature above the melt temperature of the polypropylene to form a molten mass;
- charging pellets that include a blend of a propylene-based elastomer and stannous chloride to the twin-screw extruder through an inlet in a barrel downstream of the initial mix zone, where the propylene-based elastomer comprises propylene-derived units and 5 to 30 wt % of α-olefin-derived units and where the propylene-based elastomer has a melting temperature of less than 120° C. and a heat of fusion of less than 75 J/g;
- heating the pellets above the melt temperature of the propylene-based elastomer and mixing the molten pellets with the molten mass;
- charging a phenolic resin curative to the twin-extruder through an inlet in a barrel downstream of the barrel where the pellets are charged;
- mixing the phenolic resin with the molten mass while transferring the molten mass through a cure zone where dynamic vulcanization of the ethylene-propylene-diene copolymer takes place to thereby form a thermoplastic vulcanizate;
- removing the thermoplastic vulcanizate from the twin-screw extruder;
- cooling the thermoplastic vulcanizate;
- and
- pelletizing the thermoplastic vulcanizate.
Dependencies are inferred from the claim text.